I got the file from the Joda site and followed these instructions for adding libraries but when I get to the Gradle sync I end up with the error:
Gradle Syn
I completely prefer to use jitpack.io repository.
In this case, you should get GitHub links of joda-time (just a simple search) and go to Jitpack.IO then search for the github link.
After all, you should get this page and do the instructions.
https://jitpack.io/#JodaOrg/joda-time/v2.9.4
Just sync your gradle and all done...